Maryland Live Casino blackjack table, viewed through a surveillance camera. (Maryland Live Casino)

[This post has been updated.]

A Northern Virginia couple who bet that they could get away with using doctored chips at Maryland Live has been charged, just weeks after another pair were charged in a similar fake-chip scheme, authorities say.

Ngan S. Nguyen, 29, and his girlfriend, Dung N. Vo, 35 — both from Herndon in Fairfax County — were each charged with one count of felony theft, one count of conspiracy to commit felony theft and two other felony-theft-related counts. The charges were issued by the Anne Arundel County District Court Commissioner’s office, though neither Nguyen nor Vo has yet been served with a criminal summons.

Investigators used surveillance footage as well as driver’s license data to record the alleged crimes, which they said were committed throughout the state’s largest casino.

Nguyen and Vo are suspected of altering numerous white $1 chips from Hollywood Casino at Charles Town Races in West Virginia to make them look like black $100 chips from Maryland Live, according to a Virginia court document.

The couple arrived at the Arundel Mills gambling palace two nights before Thanksgiving, the document says, and proceeded to one of the table-game pits. Vo sat down and gave the dealer “several” fake black chips in exchange for “approximately $400″ worth of green $25 chips, then moved to a nearby table, where she lost a hand and then headed to the cashier’s cage, the documents allege.

There, Vo exchanged two black chips and numerous greens for $625. She and Nguyen left Maryland Live less than 75 minutes after their arrival, having left at least 10 fake $100 chips behind, according to the court document; the fakes were ”easily identified as counterfeit.”

Investigators say they think the couple also passed counterfeit chips at the Charles Town casino.

The charges surfaced about a month after Rosa A. Nguyen and Vuong Q. Truong — both of Annandale in Northern Virginia — were charged with multiple theft and theft-related counts.

Truong has admitted to Maryland State Police that he purchased counterfeit casino chips on the Internet — paying $12,000 for $150,000 worth, authorities said. The chips appeared similar to Maryland Live’s black $100 chips, and approximately $4,000 in fakes were recovered from the casino.

Most of the rest were dumped in Lake Accotink, not far from Truong and Rosa Nguyen’s home.

“Fortunately for police, the chips floated,” a Maryland State Police news release said. Authorities recovered about $115,000 worth of counterfeit casino chips from the water.